/** 
 * @Title:TODO  
 * @Desription:TODO
 * @Company:CSN
 * @ClassName:MessageUtil.java
 * @Author:fangdong
 * @CreateDate:2014年7月22日   
 * @UpdateUser:fangdong  
 * @Version:0.1 
 *    
 */ 

package com.credit.weixin.util;

import java.io.InputStream;
import java.io.Writer;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;

import org.dom4j.Document;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;

import com.credit.weixin.message.resp.TextMessage;
import com.credit.weixin.message.resp.Article;
import com.credit.weixin.message.resp.MusicMessage;
import com.credit.weixin.message.resp.NewsMessage;
import com.thoughtworks.xstream.XStream;
import com.thoughtworks.xstream.core.util.QuickWriter;
import com.thoughtworks.xstream.io.HierarchicalStreamWriter;
import com.thoughtworks.xstream.io.xml.PrettyPrintWriter;
import com.thoughtworks.xstream.io.xml.XppDriver;

/** 
 * @ClassName: MessageUtil 
 * @Description: 消息工具类 
 * @author: fangdong 
 * @date: 2014年7月22日
 * 
 */
public class MessageUtil {
    //返回消息类型：文本
    public static final String RESP_MESSAGE_TYPE_TEXT = "text";
    //返回消息类型：音乐
    public static final String RESP_MESSAGE_TYPE_MUSIC = "music";
    //返回消息类型：图文
    public static final String RESP_MESSAGE_TYPE_NEWS = "news";
    //请求消息类型：文本
    public static final String REQ_MESSAGE_TYPE_TEXT = "text";
    //请求消息类型：图片
    public static final String REQ_MESSAGE_TYPE_IMAGE = "image";
    //请求消息类型：链接
    public static final String REQ_MESSAGE_TYPE_LINK = "link";
    //请求消息类型：地理位置
    public static final String REQ_MESSAGE_TYPE_LOCATION = "location";
    //请求消息类型：音频
    public static final String REQ_MESSAGE_TYPE_VOICE = "voice";
    //请求消息类型：推送
    public static final String REQ_MESSAGE_TYPE_EVENT = "event";
    //事件类型：subscribe(订阅)
    public static final String EVENT_TYPE_SUBSCRIBE = "subscribe";
    //事件类型：unsubscribe(取消订阅)
    public static final String EVENT_TYPE_UNSUBSCRIBE = "unsubscribe";
    //事件类型：CLICK(自定义菜单点击事件)
    public static final String EVENT_TYPE_CLICK = "CLICK";
    
    /**
     * 解析微信发来的请求（XML）
     * @param request
     * @return
     * @throws Exception
     */
    @SuppressWarnings("unchecked")
    public static Map<String,String> parseXml(HttpServletRequest request) throws Exception{
        //将解析结果存储在HashMap中
        Map<String,String> map = new HashMap<String,String>();
        
        //从request中取得输入流
        InputStream inputStream = request.getInputStream();
        //读取输入流
        SAXReader reader = new SAXReader();
        Document document = reader.read(inputStream);
        //得到xml根元素 
        Element root = document.getRootElement();
        //得到根元素的所有子节点
        List<Element> elementList = root.elements();
        
        //遍历所有子节点
        for(Element e : elementList){
            map.put(e.getName(), e.getText());
        }
        
        //释放资源
        inputStream.close();
        inputStream = null;
        
        return map;
    }
    /**
     * 文本消息对象转换成xml
     * @param textMessage 文本消息对象
     * @return
     */
    public static String textMessageToXml(TextMessage textMessage){
        xstream.alias("xml", textMessage.getClass());
        return xstream.toXML(textMessage);
    }
    
    /**
     * 音乐消息对象转换成xml
     * @param musicMessage 音乐消息对象
     */
    public static String musicMessageToXml(MusicMessage musicMessage) {
        xstream.alias("xml", musicMessage.getClass());  
        return xstream.toXML(musicMessage);
    }
    
    /**
     * 图文消息对象转换成xml
     * @param newsMessage 图文消息对象
     * @return
     */
    public static String newsMessageToXml(NewsMessage newsMessage) {
        xstream.alias("xml", newsMessage.getClass());  
        xstream.alias("item", new Article().getClass());  
        return xstream.toXML(newsMessage);
    }
    
    /**
     * 扩展xstream，使其支持CDATA块
     */
    
    private static XStream xstream = new XStream(new XppDriver(){
        public HierarchicalStreamWriter createWriter(Writer out){
            return new PrettyPrintWriter(out){
                //对所有xml节点的转换都增加CDATA标记
                boolean cdata = true;                
                @SuppressWarnings("unchecked")
                public void startNode(String name,Class clazz){
                    super.startNode(name, clazz);
                }                
                protected void writeText(QuickWriter writer,String text){
                    if(cdata){
                        writer.write("<![CDATA[");  
                        writer.write(text);  
                        writer.write("]]>"); 
                    }else{
                        writer.write(text);  
                    }
                }
            };
        }
    });
    
}
